The present invention relates to an input/output unit, an input/output method, and a receiving unit. In particular, the present invention relates to an input/output unit, an input/output method, and a receiving unit suitable for use with an IRD (Integrated Receiver and Decoder) and an STB (Set Top Box) that receive digital broadcast data.
As the number of satellites is increasing and facilities for digital satellite broadcasts are improving, digital satellite broadcasts are becoming common.
In digital satellite broadcasts, digital data as broadcast programs are often scrambled so as to charge subscribers for programs that they have viewed and listened to and to prevent non-subscribers from viewing and listening to the broadcast programs. When digital data is descrambled for a subscriber, the IRD may store charging information.
When digital video data and digital audio data as broadcast programs are encoded corresponding to for example MPEG (Moving Picture Experts Group) standard and transmitted as an MPEG transport stream (hereinafter referred to as TS), the IRD extracts transport packets (hereinafter referred to as TS packets) of a desired channel (program) from descrambled data and supplies decoded picture and decoded sound to the subscriber (user).
Recently, a system that allows a digital VTR (Video Tape Recorder) to record digital broadcast data received from the IRD and the IRD to decode data reproduced by the VTR has been proposed.
In such a system, it is convenient to allow the IRD to output data that has not been descrambled (non-descrambled data) and an external unit to input data that has not been descrambled (non-descrambled data) or that has been descrambled (descrambled data) to the IRD.
It may be desired that the descrambling process and the charging process be performed by an external unit rather than the IRD. To do that, digital data that has not been descrambled should be output from the IRD to the external unit. When the external unit does not have an MPEG decoder, the external unit should output descrambled data to the IRD.
The present invention is made from the above-described point of view. An object of the present invention is to allow a receiving unit (such as an IRD) that receives digital data to flexibly input and output data.
An input/output according to one aspect of the invention is an input/output unit for managing data that is input and output between a receiving unit and an external unit, the receiving unit having receiving means for receiving digital data that has been scrambled at least partly and descramble means for descrambling the digital data, the input/output unit comprising an input/output controlling means for supplying digital data that is received from the receiving means or descrambled data that is received from the descramble means to the external unit and supplying data that is received from the external unit to the descramble means of the receiving unit, the descrambled data being digital data descrambled by the descramble means, and an interface between the input/output controlling means and the external unit.
A receiving unit according to another aspect of the invention is a receiving unit, comprising a receiving means for receiving digital data that has been scrambled at least partly, a descrambling means for descrambling the digital data, an input/output controlling means for supplying digital data that is received from the receiving means or descrambled data that is received from the descramble means to an external unit and supplying data that is received from the external unit to the descramble means, the descrambled data being digital data descrambled by the descramble means, and an interface between the input/output controlling means and the external unit.
An input/output method according to a further aspect of the invention is an input/output method for inputting and outputting data between a receiving unit and an external unit, the receiving unit having receiving means for receiving digital data that has been scrambled at least partly and descramble means for descrambling the digital data, the input/output method comprising the steps of supplying digital data that is received from the receiving means or descrambled data that is received from the descramble means to the external unit and supplying data that is received from the external unit to the descramble means of the receiving unit, the descrambled data being digital data descrambled by the descramble means.
In the input/output unit, the input/output controlling means supplies digital data that is output from the receiving means or descrambled data that is output from the descramble means to the external unit. In addition, the input/output controlling means supplies data that is output from the external unit to the descramble means of the receiving unit.
In the receiving unit, the input/output controlling means supplies digital data that is output from the receiving means or descrambled data that is output from the descramble means to the external unit. In addition, the input/output controlling means supplies data that is output from the external unit to the descramble means of the receiving unit.
In the input/output method, digital data that is output from the receiving means or descrambled data that is output from the descramble means is supplied to the external unit. In addition, data that is output from the external unit is supplied to the descramble means of the receiving unit.